Recent formal models of pedagogy (Shafto & Goodman, 2008) assume that teachers provide evidence likely to increase the learners belief in a target hypothesis. Thus in pedagogical contexts, the learner can infer that evidence is not merely true of the concept but representative of it. If for instance, a teacher demonstrates a single function of a toy, the learner should assume that only that function exists. What happens when a teacher violates these pedagogical sampling assumptions (e.g., showing only one function of a toy with many functions)? If the learner discovers that the evidence is incomplete, does the learner evaluate the teacher accordingly? Here we show that, much as learners are sensitive to cases when informants are inaccurate (sins of commission), both adults and children are sensitive to sins of omission and penalize teachers who provide information that is accurate but incomplete.